For millennia, dogs have been our companions, working partners, and family members. The story of our species is deeply interwoven with theirs. But how did this incredible diversity in dogs emerge, and how far back does this relationship with humans truly go? Two new studies published in Science provide compelling answers, revealing a far older and more complex history than previously thought.
The Origins of Modern Dog Diversity
The studies suggest that the foundations for the wide range of shapes and sizes we see in dogs today weren’t solely the result of recent selective breeding. Significant physical variation emerged thousands of years earlier.
One study, led by Allowen Evin from the University of Montpellier, analyzed 643 dog and wolf skulls spanning 50,000 years. The results show that the distinctive “dog-like” skull shape first appeared around 11,000 years ago, during the Holocene epoch (the period since the last ice age).
Interestingly, researchers re-examined 17 previously studied skulls from the Late Pleistocene (129,000 to 11,700 years ago), including some identified as early dogs. They found all of these ancient skulls were essentially wolf-like in shape. This suggests that while the split between wolves and dogs likely occurred earlier, the skull shape of early dogs didn’t begin to change significantly until the Holocene.
This means early dogs were far more diverse than previously assumed, laying the groundwork for the extreme variations we see today.
Traveling Companions: Dogs as Cultural Markers
Earlier genomic studies identified four major dog lineages dating back roughly 20,000 years: Eastern (East Asia and Arctic) and Western (Europe and Near East). Understanding how these lineages shifted over time can reveal clues about ancient human movements.
A second study, led by Shao-Jie Zhang from the Kunming Institute of Zoology, analyzed 73 ancient dog genomes spanning the last 10,000 years to trace human-dog movements across Eastern Eurasia. The findings reveal multiple shifts in dog ancestry that correlate with the movement of specific human groups – hunter-gatherers, farmers, and pastoralists.
This suggests that dogs often moved with their human companions, carrying unique genetic signatures across the landscape. In some cases, there were discrepancies: Eastern hunter-gatherers with ties to Western Eurasia had largely Arctic dogs, despite Western Eurasian cultures having Western dogs at the time.
This discrepancy implies dogs played a role in cultural exchange or trade. They weren’t just acquired after relocation; they were taken on journeys, acting as “biocultural packages” alongside humans.
Reshaping Our Understanding
Together, these studies reshape our understanding of how dogs became so diverse and how their relationship with humans evolved. The genetic and morphological foundations for modern variation were laid thousands of years ago, shaped by natural selection, human influence, and diverse environments.
The findings highlight that the bond between humans and dogs is ancient, complex, and far more intertwined than previously thought. Studying ancient dog genomes can act as a living record of human migrations, trade networks, and cultural exchanges.
Future research investigating physical diversity and ancestry through time could deepen our understanding of canine origins and spread. Whatever their beginnings, this research reinforces the unique and enduring bond between humans and dogs, a partnership almost as diverse as canines themselves
